Argentinosaurus huinculensis was discovered in 1987, when Guillermo Heredia, a rancher, discovered its shinbone. It was described in 1993 by José F. Bonaparte and Rodolfo Coria.

The holotype was found in the Huincul Formation in the Northwestern part of Río Negro in Argentina. Only one specimen has ever been found.

Argentinosaurus is thought to be a basal titanosaur from the antarctosauridae family. Titanosaurs were the largest sauropods ever discovered, and were also the last surviving sauropods at the end of the Cretaceous.

The holotype consists of some vertebrae, ribs, a fibula, and a partial femur. Gregory S. Paul's reconstruction in the early 1990s estimated the length to be between 25 and 30 metres, and the weight to be between 80 and 100 tonnes. More recent comparisons with other titanosaurs, have put the size estimations at 22-26 metres and the weight around 83.6 tonnes. This would make Argentinosaurus the largest dinosaur discovered.

It is believed that Argentinosaurus was preyed upon by Giganotosaurus, the largest therapod discovered.

The holotype of Argentinosaurus is set up on display at the Museo Carmen Funes in Plaza Huincil, where its assembled length is 39.7 metres, with a height of 7.3 metres. Simulations done in 2013 based off of this reconstruction estimate the movement speed of Argentinosaurus at around 2m/s, or 7km/h.

Argentinosaurus was an herbivore, as with all sauropods. Being the size that it was, and the energy needed to maintain the creature, being a land-based carnivore was just not feasible.

"Argentinosaurs" refers to the country the dinosaur was discovered in, Argentina. "Huinculensis" is in reference to the Huincul Formation, where the fossils were discovered.